Silicon-carbon composite, negative electrode comprising same, secondary battery using silicon-carbon composite, and method for preparing silicon-carbon composite

1. A silicon-carbon composite comprising:

a carbon assembly having a plurality of carbon nanowires or carbon nanotubes assembled, and having mesopores perforated in a length direction between a plurality of the carbon nanowires or the carbon nanotubes; and

a silicon-based material provided in the mesopores of the carbon assembly,

wherein a percentage of the mesopores provided with the silicon-based material is greater than or equal to 20% and less than or equal to 95% based on the total mesopores of the carbon assembly.

2. The silicon-carbon composite of claim 1 , wherein the carbon assembly is obtained by a plurality of the carbon nanowires or the carbon nanotubes being uniformly distributed in a hexagonal form and assembled.

3. The silicon-carbon composite of claim 1 , wherein the silicon-based material includes at least one of a silane-based compound, silicon, and lithiated silicon.

4. The silicon-carbon composite of claim 1 , wherein the silicon-based material is a silicon-based particle.

5. The silicon-carbon composite of claim 4 , wherein a diameter of the silicon-based particle provided in the mesopores of the carbon assembly corresponds to a diameter of the mesopore of the carbon assembly.

6. The silicon-carbon composite of claim 1 , wherein a diameter of the mesopore of the carbon assembly is 100 nm or less.

7. The silicon-carbon composite of claim 1 , wherein the carbon assembly is a carbon assembly particle.

8. The silicon-carbon composite of claim 7 , wherein a diameter of the carbon assembly particle is greater than or equal to 0.1 μm and less than or equal to 10 μm.

9. The silicon-carbon composite of claim 1 , wherein a mass ratio of the carbon assembly and the silicon-based material is from 1:1 to 1:5.

10. A negative electrode comprising the silicon-carbon composite of claim 1 .

11. A secondary battery comprising:

a positive electrode;

a negative electrode including the silicon-carbon composite of claim 1 ; and

a separator provided between the positive electrode and the negative electrode.

12. A battery module including the secondary battery of claim 11 as a unit battery.

13. A method for preparing the silicon-carbon composite of claim 1 comprising:

penetrating a silicon-based compound into mesopores of a carbon assembly having the mesopores perforated in a length direction between a plurality of carbon nanowires or carbon nanotubes by assembling a plurality of the carbon nanowires or the carbon nanotubes.

14. The method for preparing a silicon-carbon composite of claim 13 , wherein the silicon-based compound penetrating into the mesopores of the carbon assembly includes at least one of a silane-based compound, silicon, and lithiated silicon.

15. The method for preparing a silicon-carbon composite of claim 13 , wherein the step of penetrating the silicon-based compound into mesopores of the carbon assembly is penetrating a silane-based compound into the mesopores of the carbon assembly.

16. The method for preparing a silicon-carbon composite of claim 15 , wherein the silane-based compound is silane or halogenated silane.

17. The method for preparing a silicon-carbon composite of claim 13 , further comprising:

heat treating the carbon assembly into which the silicon-based compound penetrates.

18. The method for preparing a silicon-carbon composite of claim 17 , further comprising:

reacting the silicon-based compound penetrating into the heat treated carbon assembly with lithium metal or iodized lithium.

19. The method for preparing a silicon-carbon composite of claim 13 , wherein the step of penetrating the silicon-based compound into mesopores of the carbon assembly is penetrating a silane-based compound into the mesopores of the carbon assembly, and further comprising:

heat treating the carbon assembly into which the silane-based compound penetrates; and

reacting the carbon assembly with lithium metal or iodized lithium after the heat treatment.